[StanFromIreland]

Preserves existing behavior for tests (c_module would just be the Python implementation) other than the one failing.

• Issue: test.test_zoneinfo.test_zoneinfo.ExtensionBuiltTest.test_cache_location fails if _zoneinfo Cextension isn't built #120965

[StanFromIreland]

Requesting @pganssle since is maintainer of zoneinfo (If I recall correctly)

[pganssle]

I don't remember offhand, but I feel like the purpose of this test is to make sure nothing accidentally disables the zoneinfo C extension build, so disabling it if the C extension didn't get built seems counter-productive.

Is there a way to detect if it was intentionally not built? Something in sysconfig or something like that? Under what circumstances is it being deliberately disabled? If it is just pypy, do they have a preferred mechanism for communicating that a test like this can be skipped, preferably one that doesn't also make our tests more fragile?

[pganssle]

Oh the docstring is maybe a little misleading, I think I remember this now. It's not testing that the C extension got built, it is making sure that the zoneinfo constructor isn't returning cached values from the wrong implementation. I think. I will have to look at this a bit later to convince myself 100% that it's not also the other thing, though.

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[StanFromIreland]

Oh the docstring is maybe a little misleading, I think I remember this now. It's not testing that the C extension got built, it is making sure that the zoneinfo constructor isn't returning cached values from the wrong implementation. I think. I will have to look at this a bit later to convince myself 100% that it's not also the other thing, though.

Yep, the test checks that c_zoneinfo and py_zoneinfo are different implementations. However, _zoneinfo can be missing if Python is built with _zoneinfo disabled (e.g., in Modules/Setup.local), or in other implementations like PyPy, which currently has to patch the test:

https://github.com/pypy/pypy/blob/ddbc5c1cbe7536b02f4fde697e7fab700b1fe0c5/lib-python/3/test/test_zoneinfo/test_zoneinfo.py#L1918-L1919

In those cases there is only one implementation so zoneinfo falls back to the pure-Python class, so there is no second implementation to mix up and nothing for this test to guard. The rest of the suite still runs against the Python class, so no coverage is lost.

[miss-islington-app]

Thanks @StanFromIreland for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

[miss-islington-app]

Thanks @StanFromIreland for the PR 🌮🎉.. I'm working now to backport this PR to: 3.15.
🐍🍒⛏🤖

[bedevere-app]

GH-160469 is a backport of this pull request to the 3.14 branch.

[bedevere-app]

GH-160470 is a backport of this pull request to the 3.15 branch.